In constructing buildings, it is common to attach cladding components (e.g., girts, purlins, panels, roofing, etc.) to supportive building components (e.g., steel stud wall studs, concrete or masonry walls, floors, roofs, and other back-up supports). In many applications, it is preferable to provide space between cladding components and the building components for insulation as well as to achieve other performance characteristics including durability. This is typically done by attaching supporting cladding components with spacers or other supports to a back-up structure.
FIG. 1 is a perspective view of an exterior wall assembly 10 that illustrates use of prior art spacers to connect cladding components to supporting building components. Assembly 10 comprises a wall 12 formed by interior finish 14 such as a drywall board, a C-shaped steel stud 16, and an exterior wall panel or sheathing 18. A moisture barrier 20 may cover exterior wall sheathing 18. A galvanized steel spacer 22 is attached to steel stud 16 by screws 22A that pass through barrier 20, exterior wall sheathing 18 and at least a portion of stud 16. Spacer 22 shown in FIG. 1 is one of a plurality of like steel spacers attached to wall 12 in spaced apart, vertically aligned relation. Alternatively, continuous girts are also used to achieve this function. Spacer (or “clip”) 22 connects cladding components 24, which may consist of supporting cladding framework such as elongate vertical steel girt 26, and exterior finish 30 (e.g., stucco, metal panels, etc.), to wall 12. Girt 26 is attached by screws 24A to spacer 22. Insulation 32 may be provided in the space between wall 12 and cladding components (24, 26, and 30), and an air cavity and/or moisture drainage cavity 28 may be provided.
In assembly 10, steel spacer 22 must have sufficient strength and rigidity to support the cladding under the various loads it faces (gravity, wind, seismic, etc.). Steel or other metal clips are typically used due to their strength, stiffness, and fire resistance characteristics. Steel is also relatively inexpensive, durable and adaptable compared to other similar options such as aluminum and other metals.
A problem with wall assembly 10 is that spacer 22, being made of steel, is thermally conductive and provides a thermal bridge from cladding components 24 (and in some cases 26 and 30) to wall 12. Moreover, since spacer 22 is adjacent to steel stud 16, which is also thermally conductive, spacer 22 and steel stud 16 together provide a thermal bridge from cladding components 24 to interior wall panel 14. Since insulation 32 is provided around spacer 22 (and in some cases around the steel stud 16), spacer 22 (and steel stud 16) acts an insulation bypass. As a result, it is difficult for wall assembly 10 to achieve the high levels of insulative performance demanded by modern construction standards without unduly increasing the depth of spacer 22, steel stud 16, and/or insulation 32.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.